IPC-TM-650 EN 2022 试验方法.pdf - 第174页
1.0 Outline for Methods The part is exposed to an atmo- sphere that is corrosive to the basis metal. Where there is porosity, the reagent attacks the basis metal and generates corrosion products. The part is examined for…
IPC-23241-1
Figure
1 Porosity Test Schematic
mA
VM
Power Supply
o-1 a DC
o-10 V
-
+
-
+
T
eflon®
Gold Clad Plate
Photographic Paper, Silver Halide Free
Sample Under Test
Teflon®
IPC-TM-650
Number
2.3.24.1
Subject
Porosity
Testing of Gold Electrodeposited on a Nickel Plated Copper
Substrate Electrographic Method
Date
10/85
Revision
P
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1.0
Outline for Methods
The
part is exposed to an atmo-
sphere that is corrosive to the basis metal. Where there is
porosity, the reagent attacks the basis metal and generates
corrosion products. The part is examined for corrosion prod-
ucts.
1.1
Method 1 (Nitric Acid Vapor-Gold on Copper)
This
method
applies only to gold coatings on copper and copper-
base alloys.
1.2
Method 2 (Extended Nitric Acid Vapor)
This
method
applies only to gold coatings on copper and copper-base
alloys.
1.3
Method 3 (Nitric Acid Vapor - Gold on Nickel)
This
method
applies to gold coatings on copper, copper-base
alloys, and nickel.
2.0
Nitric Acid Vapor - Gold on Copper
2.1 Apparatus
Methods
1, 2, and 3.
2.1.1
Collimated Incandescent Lamp
No.
31-33-53,
Bausch and Lomb Co., or No. 359, American Optical Co., or
equivalent.
2.1.2
Desiccator (Glass)
Fisher
Scientific Co. Series
8-595 or 8-624 or equivalent. The size of the desiccator shall
be chosen so that no more than 164 cm
3
of
air space exists
for 6.45 cm
2
of
nitric acid surface area when approximately
301 ml of acid are placed in the bottom.
Caution:
No sealant (e.g., stopcock grease, etc.) shall be
applied to the mating surfaces of the desiccator cover or
bottom. Sealants may cause these to stick together, and any
method employed to release a stuck cover is likely to be
extremely hazardous.
2.1.3
Part Support
A
supporting structure made of glass
or other material not attached by nitric acid vapors to hold the
parts under test in the upper part of the desiccator.
2.1.4
Oven
An
oven capable of drying parts at 125°C.
2.1.5
Pressure Sensitive Polytetrafluoroethylene Tape
with Silicone Adhesive Backing
Connecticut
Hard Rubber
Company TFE Type HM225 or equivalent.
2.2
Reagents
Methods
1 and 2. Nitric Acid, 69, 0 to 71.0
Percent HNO
3
.
3.0
Procedure
3.1 Method 1 (Nitric Acid Vapor-Gold on Copper)
Caution:
Perform all work in hood, since the vapors given off
are toxic. Chemical goggles, completely closing the eyes,
should be worn and eyewash facilities should be readily
available.
To
minimize and tendency for the cover to stick, press a mini-
mum of three strips of the pressure polytetrafluoroethylene
tape (adhesive side down) at equal intervals around the mat-
ting surface of the bottom of the desiccator. Place approxi-
mately 300 ml of nitric acid in the bottom of the desiccator.
Cover the desiccator and allow about 30 minutes for equilib-
rium to be established before starting the test. This equilibrium
is necessary only when the nitric acid is first placed in the
desiccator.
Clean the part with 1,1,1-trichloroethane or toluene or other
suitable solvent and dry with filtered dry air (gage pressure
less than 207 kPa (30 psi)).
Inspect the cleaned part at 10 power magnification for evi-
dence or particulate matter of the surface. If any remains,
reclean the solvent or use a clean soft brush to remove it prior
to the start of the porosity test.
Place the clean part on the support so that adequate space
exists to allow circulation of acid vapor and air around it.
Carefully remove the desiccator cover, place the support in
the desiccator and immediately replace the cover to prevent
an excessive loss of vapors that would disrupt the equilibrium
previously established. The test shall be performed at a tem-
perature of 24 ± 3°C and a maximum relative humidity of 60
percent. Unless otherwise specified, the time of exposure to
the reagent vapor shall be one hour.
2215
Sanders Road
Northbrook, IL 60062-6135
IPC-TM-650
TEST
METHODS MANUAL
Number
2.3.24.2
Subject
Porosity
of Metallic Coatings on Copper-Base
Alloys and Nickel (Nitric Acid Vapor Test)
Date
8/97
Revision
A
Originating Task Group
N/A
Material
in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only
and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.
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Remove
the part from the desiccator and immediately transfer
it to an oven at 125°C for 30 minutes. Remove and inspect
the part with 10 power magnification using the collimated
incandescent light source arranged so that the light beam
strikes the surface being examined at an angle of less than 15
degrees. The presence of blue, green, or bluish-white protru-
sions indicates that the coating is discontinuous (i.e., porous,
scratched, etc.) at these spots. The acceptable number,
sizes, and location of these protrusions shall be as specified
on the appropriate drawing or specification.
3.2
Method 2 (Extended Nitric Acid Vapor-Gold on
Copper)
Procedure
This
method is an extension of method 1 and
may be used only after the test specimen has passed the
requirements of the visual examination with the collimated
light source. The method permits the determination of the
actual sizes of the larger pores. The inspection should be per-
formed as indicated below.
After examining the oven-dried test specimen in accordance
with Method 1, brush the corrosion products from the speci-
men. Inspect the area where the corrosion products appeared
at a magnification that permits measurements of the largest
dimensions of the discontinuities with reasonable accuracy.
The acceptable distribution of pore sizes shall be as specified
on the appropriate drawing or specification.
3.3
Method 3 (Nitric Acid Vapor-Gold on Nickel)
3.3.1 Apparatus
The
apparatus described in methods 1
and 2.
3.3.2
Reagents
Nitric
acid, 69.0 to 71.0 percent HNO
3
.
Sodium
Hydroxide 10 percent by weight solution. Polysulfide
reagent.
3.3.3
Procedure
Caution:
Perform all work in a hood,
since vapors given off are toxic. Chemical goggles, com-
pletely enclosing the eyes, should be worn and eye wash
facilities should be readily available.
Use the procedure for Method 1 up to removal from nitric acid
vapors.
At the end of the one hour exposure to the nitric acid vapors,
remove the part from the desiccator and immediately dip it in
the 10 percent by weight sodium hydroxide solution for 25 to
30 seconds at room temperature. Rinse the part with water
and then dip it for 25 to 30 seconds in the polysulfide reagent
at room temperature. Then rinse it in water and dry using fil-
tered compressed air (gage pressure less than 207 kPa).
Inspect the part at 10 power magnification. The presence of
black corrosion products is evidence of porosity. The accept-
able number, sizes, and locations of pores shall be as speci-
fied on the appropriate drawing or specification.
3.4
Polysulfide Reagent Makeup
Dissolve
sodium sulfide
crystals in water until solution is saturated. Add excess flow-
ers of sulfur (more than 250 grams per 1000 ml). Stir and
allow solution to stand 24 hours. Filter and dilute with water to
a specific gravity of 1.142 at room temperature as defined in
ASTM Designation E 41. The solution should be a red-orange
color.
To check reagent effectiveness, dip a clean copper or high
(more than 95 percent) copper alloy specimen into the reagent
at room temperature as defined in ASTM Designation E 41. It
shall blacken within 10 seconds.
IPC-TM-650
Number
2.3.24.2
Subject
Porosity
of Metallic Coatings on Copper-Base Alloys and Nickel
(Nitric Acid Vapor Test)
Date
8/97
Revision
A
P
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